96 GEOLOGICAL NOTES ON COAL AND IRON ORE 



These Triassic sediments have probably been formed 

 during a warmer and more arid climate than has been the 

 case with the Permian ones. 



4. — Lower Jurassic Coal Series, 22 found in N. W. Central and N. 

 Shansi built up mainly of grey or white sandstones and 

 blue or green and black argillaceous shales. In the 

 Ta-T'ung basin in N. Shansi this occurs according to 

 C. C. Wang in very much varying thicknesses up to 480 

 metres. 



5.— Upper Jurassic Eed Series (C. C. Wang),' 22 consisting of red 

 and green sandstones and argillaceous shales. 



Within this complex (1 to 5) of which the total minimum 

 thickness amounts to 1,500 metres, at least two unconformi- 

 ties seem to exist, a probable one in the marginal district of 

 the Taiyuan basin between the Upper Carboniferous and 

 Lower Permian (Eothliegende), and one has been pointed out 

 by C. C. Wang in N. Shansi between the Triassic and the 

 Lower Jurassic. Between the Permian and the Triassic no 

 unconformity has been discovered; on the other hand the 

 translation here between Paleozoic and Mesozoic is marked 

 by indications of climatic change. 



The main part of the mineral wealth of Shansi is bound 

 to the Carboniferous series of sediments. The most im- 

 portant products that are won here are coal, iron and 

 sulphor. The tenure of pyrites in the carboniferous layers are 

 also indirectly the source of the Gypsum, which in many 

 places occurs in workable quantities within brecciated zones 

 in the ordovician limestone. 



Apart from the material supplied by the cambro-ordo- 

 vican sediments in the form of building stone, lime and the 

 above-mentioned secondary Gypsum,, this formation and its 

 pre-cambrian substratum offer only small quantities of 

 useful minerals. The same holds good for the Permian 

 and Triassic sediments. In Central, Eastern and Southern 

 Shansi, the mineral resources are concentrated to the zone 

 of comparatively inconsiderable thickness which is con- 

 stituted of the Carboniferous and, in S.E. Shansi, also the 

 Permo-Carboniferous of the "Shansi Formation." It is 

 therefore to be recommended from a practical point of view 

 to define this zone with the new name "The Economic 

 Zone of Shansi." 



The sediments of the carboniferous coal-series in Central 

 Shansi attain a thickness of 150 to 250 metres. The most 



22 According to C. C. Wang : r "The Coal Field of Ta-T'ung, 

 Shansi" Bull. Geol.-Surv. of China,' November 3, 1921, page 71. 



